Invisible electric burglar and fire alarm.



PATENTED MAY 5, 1908.

J. W. DAWSON. INVISIBLE ELECTRIC BURGLAR AND FIRE ALARM.

APPLIGATIGN FILED SEPT. 12, 1907.

Z ZZW gagemcnt with contact 4; from battery l. through conductor 2,switch 3, ontact 4, conductor 14, conductor 18, contact 19, c1!" cuitmaker 2! conductor 1!), conductor 20, conductor 16, binding post .7,through conductor f5, eleetro-magnet J, conductor 10, the alarmmechanism 11 and conductor 12 back to the battery. The establishment ofthis circuit starts the operation of the alarm mechanism and theenergization of the magnet attracts the armature or drop 11- until thesame engages contact 7, the result being the conductors H, 15, 1t), 20,2t), and It), a e cut out of the circuit and the current follows theshorter or local circuit from the hattery through conductor 2, switch 3,contact 4, conductor 5, armature or stop 6 contact 7, conduct-or h,elcctro-magnet J. conductor 10, alarm mechanism 1 conductor t2 back tothe battery. it will thus he seen that. this local circuit causes theringing of the boil after being once established irrespective of theexistence of conductors l4 and l6 and those connected with them. if thethread instead of hrcaking should ell'cct the withdrawal of the circuitbreaker 24 from between the members of contact 15, said arms will springtogether and thc circuit will be from contact 4, through conductor 14.contact-15 and conductor ltior if anything should. prevent theniembcrsoi contact 15 from completing the circuit the circuit maker 2!will drop as hcreinbcl'orc cxplained and establish a connection betweencontact members 19. It will thus be seen that there is practically nodanger of failure to complete a circuit from the battery in the event ofthe 5 breaking of the. thread or the pulling thereby of the circuitbreaker from between the memhers of Spring contact 15.

It will be understood of course that thc breaking of the thread from anycause, such for instance as lire, will set the alarm in operation and inthis case notice will be given to the person in charge beforeirreparable damage is done.

From the. above description it will be apparent that l have produced ahur lar and lire alarm mechanism possessing the eatures of advantageenumerated as desirable and I wish it to be understood that I do notdesire to be restricted to the exact details of construction shown anddescribed as obvious modifications will suggest themselves to oneskilled in the art.

Having thus described the invention what I claim as new and desiretosecure by Letters Patent, is

1. A signal system, comprising a battery, an alarm mechanism, a pair ofspring contac s, a second pair of spring contacts one of each beingelectrically connected together and to the. positive pole of thebattery, conductors connecting the other pair of contacts with the alarmmechanism and the negative pole of the battery, :1 thread suitablyguided and having an insulating plate between a pair of said springcontacts to hold them apart and pent mg circuit-maker ield above and outof contact with the other pair of spring contacts and adapted in thcevent of the breaking of the threadm of the witlnlrawal of theinsulating platel'rom the path of the first-named contacts to dropbetween and electrically connect said separated spring contacts.

2. In an alarm mechanism. a battery, an cli-ctro magnet, an alarmmechanism, a contact connected to the magnet and in uninterruptedcircuit with the signal mechanism and one pole of th batter an armatureor drop connected to the opposite side of the battery and adapted whenthe magnet i energized to engage said contact and establish contactselectrically connect d respectirely to the first-named contact and thepole of the battery to which the armature is connected, and a thread-sup)ortcd means for ctl'ecti v the completion oi the circuit between saispring contacts.

in testimom whereof I aiiix my signature;

in the presence of two witnesses.

JAMES W. DAWSON.

'Wi messes H. C. RODGERS,

. Y. THORPE.

rovided atits op osit end with a (lo-- I a l cal circuit through thealarm mechanism, '85

